Clinical features of isolated gestational proteinuria progressing to pre-eclampsia: retrospective observational study

Objectives Some women with isolated gestational proteinuria (IGP) later develop hypertension and are diagnosed with pre-eclampsia (PE). This study was performed to determine whether clinical features of such proteinuria preceding PE (P-PE) differ from those of other PE (O-PE). Design Retrospective observational study after approval of the institutional review board of ethics. Setting A single university hospital. Proteinuria was defined as a protein-to-creatinine ratio (mg/mg; P/Cr) of 0.27 in the spot urine specimen. IGP was defined as proteinuria in the absence of hypertension. P-PE was defined as PE in which proteinuria preceded hypertension by more than 2days. Participants All of 10 and 18 consecutive women with P-PE and O-PE, respectively, who gave birth between January 2008 and August 2013. Results Proteinuria appeared earlier (at 30.23.0 vs 35.3 +/- 4.3weeks, p=0.001), the P/Cr level was greater at birth (7.28 +/- 2.14 vs 3.19 +/- 2.49, p<0.001), net maternal weight gain during the last antenatal 1week was greater (3.1 +/- 1.8 vs 1.3 +/- 1.7kg, p=0.023) and length of pregnancy was shorter (32.5 +/- 1.9 vs 36.1 +/- 3.6weeks, p=0.001) in women with P-PE than in O-PE. The duration of IGP was 10.0 +/- 5.9days (range 3-20), and the time interval until delivery after diagnosis of PE was 6.1 +/- 8.2days (range 0-23) in 10 women with P-PE. The P/Cr levels at birth were significantly inversely correlated with the antenatal lowest antithrombin activity and fibrinogen levels among the 28 women with PE. Conclusions Women with P-PE were likely to exhibit greater proteinuria in the urine, greater water retention in the interstitial space and more enhanced coagulation-fibrinolysis, thus suggesting that they may constitute a more severe form of PE than women with O-PE do.